One of the most frustrating things to have to experience, especially if you're a person who loves to use a bicycle, is a bent rim. Bent rims happen and are entirely too common, but does this mean that the whole thing needs to be thrown out after getting a bent rim? Is the rim entirely useless? Can a bent bicycle rim be fixed?
If it's bad enough, you may need to "true" (AKA "straighten") the rim yourself. Depending on how bad the damage is, you may be able to fix your own and save yourself from buying a new one. With that in mind, here's how to true a bike wheel.
When deciding how to true a bike wheel, you'll need to figure out how bad the bend is. Bent rim repair ranges from mild cosmetic damage to a severely bent wheel, depending on what the rim has been through. Your rim can get bent from hitting one pothole too many, curb damage from the street, twisting when getting in or out of a bike rack, or a spoke break. It's not uncommon at all to have a mildly bent rim that you can hardly even notice off the get-go. Typically, a mildly bent rim is realized after hearing a strange noise coming from the rim itself. A mildly bent rim can still work, but it'll slow you down.
For checking spokes, you can easily make sure your spokes are in tip-top shape by using a spoke tool or spoke wrench, which comes in several different sizes and should be part of your bike tool kit. The spokes are just as important as the rim itself, so make sure your spokes are healthy and perform maintenance in this department as needed.
For best results during the wheel straightening process, consider using a bicycle wheel truing stand. Using a bike stand keeps the bike in place while repairing loose spokes or a bent wheel. If you don't have a bicycle wheel truing stand, your local bike shop should have one, as well as other tools for basic wheel repairs. If the wheel damage is bad enough, you might consider getting a new wheel (or a temporary replacement wheel until you can perform regular wheel repair service to it).
Using a Spoke Wrench
Pro bike shops have some pretty nifty machines that will take the rim off a bike and test the frame of the rim on a spinning stand. You don't need to do this unless you are working on a racing or professional bike, but you can do this if you want to make sure the rim is completely straight. However, this is not needed if you need to fix a bent rim on a regular road bike. You can easily use the spoke wrench to remove the entire rim if needed.
You're going to want to turn the bike over so you can access the wheels. The bike will sit comfortably on the seat and handlebars, so you don't even have to remove the wheels from the bike. Then, using your spoke wrench, carefully measure and straighten out each spoke to straighten out the rim. If the spokes are straight, the rim will straighten as well. This is a nifty tool because you won't believe how easy it is to straighten all the spokes resulting in a straightened rim. The spoke key (spoke wrench) keeps everything straight and working properly.
Severe Bent Rim
If the bike rim is severely bent, you'll feel a wobble while you ride on that tire. You could try using the spoke key to help with the spokes, but the actual rim will need to be straightened, maybe by hand. Going back to that tuning wheel used by professionals would be an option to get everything up and work again. If the main kinks in a wheel are worked out, then the spoke key will come in and make sure everything else is straight and ready to go. This major dent could be put relatively back into place by turning the bicycle upside down and using a hammer to lightly tap the rim back into the general place. Then, with that wonderful spoke key, you can straighten out each spoke to ultimately straighten the entire rim back into place.
If something really crazy has happened to the rim and the rim is bent severely, even lightly tapping it back into place could result in a cracked or broken rim. Even the process of tapping it back into place could cause the entire rim to snap, clearly making this irreplaceable. This is when you need to go out and buy yourself a brand new rim. The spoke key and bending back into shape will only work if the rim is only slightly bent. Otherwise, riding on a severely bent rim could result in serious bicycle-related injury or even destroy your bike if you try to ride on it.
A bent rim can seriously damage your rim brake pads if you're not careful. If you start to notice a strange sound coming from your spokes or bike rim, make sure that the bent rim is not pressing against the rim brake pads. Over time, if a rim is pressing against the brake pad, even lightly, the rim could seriously damage the pads, possibly causing a horrible accident later on. Rim brakes are delicate and have an important job, so make sure you take good care of them. It's important to take every sound you hear seriously so you can prevent any damage or injury in the future.
The key to truing a bent bicycle rim lies in getting a really great spoke key. The wheel straightening process requires the right tools to fix your damaged wheel. Again, if the rim is severely bent, there isn't much you can do about it. We put all of our weight upon our bikes, which lay on the bicycle rims, so even a severe bent that has been tapped back into place could result in a huge injury if you don't tune everything correctly. Regular maintenance and care will ultimately be the factor in preserving your bike for as long as possible and ensuring your safety in the future. You can find a really good spoke key or spoke wrench at any bicycle store, but standard outdoors department stores and camping equipment stores should carry good keys, too.
At least you know you don't have to go out and buy a brand new rim for every bent rim or kink. This way, you can work out the bend yourself, preserve the longevity of your spokes, and get back to great cycling.